v4.19.13 snapshot.
diff --git a/arch/um/kernel/signal.c b/arch/um/kernel/signal.c
new file mode 100644
index 0000000..57acbd6
--- /dev/null
+++ b/arch/um/kernel/signal.c
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Licensed under the GPL
+ */
+
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/sched.h>
+#include <asm/siginfo.h>
+#include <asm/signal.h>
+#include <asm/unistd.h>
+#include <frame_kern.h>
+#include <kern_util.h>
+
+EXPORT_SYMBOL(block_signals);
+EXPORT_SYMBOL(unblock_signals);
+
+/*
+ * OK, we're invoking a handler
+ */
+static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
+{
+ sigset_t *oldset = sigmask_to_save();
+ int singlestep = 0;
+ unsigned long sp;
+ int err;
+
+ if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
+ singlestep = 1;
+
+ /* Did we come from a system call? */
+ if (PT_REGS_SYSCALL_NR(regs) >= 0) {
+ /* If so, check system call restarting.. */
+ switch (PT_REGS_SYSCALL_RET(regs)) {
+ case -ERESTART_RESTARTBLOCK:
+ case -ERESTARTNOHAND:
+ PT_REGS_SYSCALL_RET(regs) = -EINTR;
+ break;
+
+ case -ERESTARTSYS:
+ if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
+ PT_REGS_SYSCALL_RET(regs) = -EINTR;
+ break;
+ }
+ /* fallthrough */
+ case -ERESTARTNOINTR:
+ PT_REGS_RESTART_SYSCALL(regs);
+ PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
+ break;
+ }
+ }
+
+ sp = PT_REGS_SP(regs);
+ if ((ksig->ka.sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
+ sp = current->sas_ss_sp + current->sas_ss_size;
+
+#ifdef CONFIG_ARCH_HAS_SC_SIGNALS
+ if (!(ksig->ka.sa.sa_flags & SA_SIGINFO))
+ err = setup_signal_stack_sc(sp, ksig, regs, oldset);
+ else
+#endif
+ err = setup_signal_stack_si(sp, ksig, regs, oldset);
+
+ signal_setup_done(err, ksig, singlestep);
+}
+
+void do_signal(struct pt_regs *regs)
+{
+ struct ksignal ksig;
+ int handled_sig = 0;
+
+ while (get_signal(&ksig)) {
+ handled_sig = 1;
+ /* Whee! Actually deliver the signal. */
+ handle_signal(&ksig, regs);
+ }
+
+ /* Did we come from a system call? */
+ if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) {
+ /* Restart the system call - no handlers present */
+ switch (PT_REGS_SYSCALL_RET(regs)) {
+ case -ERESTARTNOHAND:
+ case -ERESTARTSYS:
+ case -ERESTARTNOINTR:
+ PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
+ PT_REGS_RESTART_SYSCALL(regs);
+ break;
+ case -ERESTART_RESTARTBLOCK:
+ PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
+ PT_REGS_RESTART_SYSCALL(regs);
+ break;
+ }
+ }
+
+ /*
+ * This closes a way to execute a system call on the host. If
+ * you set a breakpoint on a system call instruction and singlestep
+ * from it, the tracing thread used to PTRACE_SINGLESTEP the process
+ * rather than PTRACE_SYSCALL it, allowing the system call to execute
+ * on the host. The tracing thread will check this flag and
+ * PTRACE_SYSCALL if necessary.
+ */
+ if (current->ptrace & PT_DTRACE)
+ current->thread.singlestep_syscall =
+ is_syscall(PT_REGS_IP(¤t->thread.regs));
+
+ /*
+ * if there's no signal to deliver, we just put the saved sigmask
+ * back
+ */
+ if (!handled_sig)
+ restore_saved_sigmask();
+}